Open Policy Agent (OPA)
General-purpose policy engine with the Rego language for authoring and enforcing context-aware policies across services and infrastructure.
Technical Architecture & Overview
Open Policy Agent (OPA) is an open-source, general-purpose policy engine and a CNCF graduated project. It provides a declarative language called Rego that users write to create context-aware policies queried by services through an API. OPA integrates with Kubernetes, Terraform, Envoy, Kafka, and other systems. Conftest is a thin wrapper around OPA's Rego language that lets users write tests against structured configuration data such as Kubernetes manifests, Terraform code, and CI/CD definitions.
Targeted Technical Use Cases
Centralize policy decisions across microservices, admission control, and infrastructure configuration with a decoupled policy engine, and test configurations with Conftest before deployment.
Evaluation & Trade-offs
Core Strengths
- +General-purpose engine decoupled from the services it protects.
- +Rego supports complex, context-aware policies with data joins and inheritance.
- +Large ecosystem and CNCF graduated governance status.
Trade-Offs & Limitations
- -Rego has a learning curve for teams new to declarative policy languages.
- -OPA does not include built-in security policies out of the box.
- -Operational overhead of running OPA as a sidecar or standalone service.
Defensive Security Application
Deploy OPA as an admission controller or sidecar to enforce security rules, and write Conftest tests in CI to catch policy violations in IaC before they reach clusters.
Frequently Asked Questions
What is Open Policy Agent (OPA)?→
Open Policy Agent (OPA) is an open-source, general-purpose policy engine and a CNCF graduated project. It provides a declarative language called Rego that users write to create context-aware policies queried by services through an API. OPA integrates with Kubernetes, Terraform, Envoy, Kafka, and other systems. Conftest is a thin wrapper around OPA's Rego language that lets users write tests against structured configuration data such as Kubernetes manifests, Terraform code, and CI/CD definitions.
What is Open Policy Agent (OPA) used for?→
Centralize policy decisions across microservices, admission control, and infrastructure configuration with a decoupled policy engine, and test configurations with Conftest before deployment.
What are the strengths of Open Policy Agent (OPA)?→
- +General-purpose engine decoupled from the services it protects.
- +Rego supports complex, context-aware policies with data joins and inheritance.
- +Large ecosystem and CNCF graduated governance status.
What are the limitations of Open Policy Agent (OPA)?→
- +Rego has a learning curve for teams new to declarative policy languages.
- +OPA does not include built-in security policies out of the box.
- +Operational overhead of running OPA as a sidecar or standalone service.
How is Open Policy Agent (OPA) used defensively?→
Deploy OPA as an admission controller or sidecar to enforce security rules, and write Conftest tests in CI to catch policy violations in IaC before they reach clusters.